Rheumatology and Immunology Practice Questions

Q: Which of the following is an ANCA negative vasculitis?

Polyarteritis nodosa. The classification of systemic vasculitis is primarily based on the size of the vessels involved and the presence of specific biomarkers like **Anti-Neutrophil Cytoplasmic Antibodies (ANCA)** [2]. **1. Why Polyarteritis Nodosa (PAN) is the correct answer:** Polyarteritis nodosa is a **medium-vessel vasculitis**. By definition, it is **ANCA-negative**. It is characterized by necrotizing inflammation of medium-sized or small arteries without glomerulonephritis or vasculitis in arterioles, capillaries, or venules. A key diagnostic feature is its association with **Hepatitis B virus (HBV)** infection and the presence of "rosary sign" (microaneurysms) on angiography. **2. Why the other options are incorrect:** Options A, B, and D belong to the category of **ANCA-Associated Vasculitides (AAV)**, which primarily affect small vessels: * **Wegener Granulomatosis (Granulomatosis with Polyangiitis - GPA):** Strongly associated with **c-ANCA** (anti-PR3). It typically involves the triad of upper respiratory tract, lungs, and kidneys. * **Churg-Strauss Syndrome (Eosinophilic Granulomatosis with Polyangiitis - EGPA):** Associated with **p-ANCA** (anti-MPO) [1]. It is characterized by asthma, peripheral eosinophilia, and granulomatous inflammation [1]. * **Microscopic Polyangiitis (MPA):** Strongly associated with **p-ANCA** (anti-MPO). Unlike PAN, it involves small vessels (capillaries) and frequently causes pauci-immune necrotizing glomerulonephritis. **High-Yield Clinical Pearls for NEET-PG:** * **PAN Rule of Thumb:** "PAN is ANCA-negative and spares the lungs." * **c-ANCA (Cytoplasmic):** Targets Proteinase-3 (PR3); specific for GPA. * **p-ANCA (Perinuclear):** Targets Myeloperoxidase (MPO); seen in MPA, EGPA, and Primary Sclerosing Cholangitis [1]. * **Microaneurysms:** In PAN, these are commonly found in renal, mesenteric, or hepatic arteries.

Q: Which of the following is NOT an indication for intravenous immunoglobulin (IVIg)?

Systemic lupus erythematosus (SLE). **Explanation:** The correct answer is **Systemic lupus erythematosus (SLE)**. While IVIg is used in various autoimmune and inflammatory conditions, it is **not** considered a standard or first-line indication for SLE [1]. SLE is primarily managed with corticosteroids, hydroxychloroquine, and immunosuppressants (like mycophenolate mofetil or cyclophosphamide) or biologics (like Belimumab). **Why the other options are incorrect (Indications for IVIg):** * **Idiopathic Thrombocytopenic Purpura (ITP):** IVIg is a first-line treatment, especially when a rapid increase in platelet count is required (e.g., pre-surgery or life-threatening bleed). It works by blocking Fc receptors on splenic macrophages, preventing platelet destruction. * **Kawasaki Disease:** High-dose IVIg administered within the first 10 days of fever onset is the gold standard treatment. It significantly reduces the risk of developing **coronary artery aneurysms**. * **Acute Infective Polyneuritis (Guillain-Barré Syndrome):** IVIg is a mainstay of treatment, equivalent in efficacy to plasmapheresis. It helps neutralize pathogenic autoantibodies and modulate complement activation. **NEET-PG High-Yield Pearls:** 1. **Mechanism of Action:** IVIg provides passive immunity, neutralizes circulating autoantibodies, and inhibits complement-mediated damage. 2. **Other Key Indications:** Dermatomyositis (refractory), Myasthenia Gravis (crisis), Chronic Inflammatory Demyelinating Polyneuritis (CIDP), and Common Variable Immunodeficiency (CVID). 3. **Side Effect:** A classic board-favorite side effect of IVIg is **Aseptic Meningitis**. 4. **Contraindication:** Patients with **IgA deficiency** are at risk of anaphylaxis when given IVIg due to the presence of anti-IgA antibodies.

Q: What proportion of patients with Wegener's granulomatosis will have antibodies to Proteinase-3?

90%. **Explanation:** **Wegener's Granulomatosis** (now officially known as **Granulomatosis with Polyangiitis - GPA**) is a small-vessel vasculitis characterized by the triad of upper respiratory tract involvement, lower respiratory tract involvement, and glomerulonephritis. **1. Why 90% is correct:** The hallmark serological marker for GPA is the **Antineutrophil Cytoplasmic Antibody (ANCA)**. Specifically, GPA is associated with **c-ANCA** (cytoplasmic pattern), where the primary target antigen is **Proteinase-3 (PR3)**. In patients with active, generalized (systemic) disease, the sensitivity of c-ANCA/anti-PR3 is approximately **90%**. This makes it a highly specific and sensitive diagnostic tool for the condition. **2. Why other options are incorrect:** * **10%:** This is far too low. While ANCA may be negative in very early or localized disease (limited to the upper respiratory tract), it is positive in the vast majority of systemic cases. * **50%:** This represents the sensitivity of ANCA in patients with "limited" GPA (disease confined to the respiratory tract without renal involvement), but for the classic presentation of the disease, the percentage is much higher. * **100%:** In medicine, few tests are 100% sensitive. A small subset of patients (approx. 10%) remains "ANCA-negative" despite biopsy-proven GPA. **High-Yield Clinical Pearls for NEET-PG:** * **c-ANCA = Anti-PR3:** Associated with GPA (Wegener's). * **p-ANCA = Anti-MPO (Myeloperoxidase):** Associated with Microscopic Polyangiitis (MPA) and Churg-Strauss Syndrome (EGPA). * **Biopsy Gold Standard:** While ANCA is a great screening tool, the definitive diagnosis requires a biopsy showing **necrotizing granulomatous inflammation**. * **Treatment:** Induction is typically with Corticosteroids + Cyclophosphamide (or Rituximab).

Q: Which of the following statements is false regarding Familial Mediterranean fever?

Excessive production of TNF-alpha. Explanation: Familial Mediterranean Fever (FMF) is the most common hereditary autoinflammatory syndrome. The correct answer is B because the primary cytokine involved in FMF is Interleukin-1 beta (IL-1β), not TNF-alpha. 1. Why Option B is False: FMF is caused by mutations in the MEFV gene, which encodes the protein pyrin. Pyrin normally regulates the inflammasome complex. Mutated pyrin leads to the uncontrolled activation of the NLRP3 inflammasome, resulting in the excessive production and release of IL-1β. This triggers the characteristic recurrent episodes of fever and serositis (peritonitis, pleuritis, or synovitis). 2. Why Option A is True: FMF is a major cause of AA amyloidosis (secondary amyloidosis) [1]. Chronic, uncontrolled inflammation leads to high levels of Serum Amyloid A (SAA), which deposits in organs, most notably the kidneys, leading to nephrotic syndrome and renal failure [2]. 3. Why Option C is True: FMF follows an autosomal recessive pattern of inheritance, typically seen in populations of Mediterranean descent (Sephardic Jews, Turks, Armenians, and Arabs). 4. Why Option D is True: As mentioned, the MEFV gene mutation directly affects the pyrin protein, impairing its ability to inhibit the inflammatory response. High-Yield Clinical Pearls for NEET-PG: * Drug of Choice: Colchicine is the mainstay of treatment; it prevents acute attacks and, more importantly, prevents the development of AA amyloidosis [1]. * Clinical Presentation: Recurrent, self-limiting episodes of fever (lasting 1–3 days) accompanied by sterile peritonitis (mimicking acute abdomen) or pleuritis. * Erysipeloid Erythema: A pathognomonic skin rash (red, swollen area typically on the lower legs or dorsum of the foot) seen in FMF.

Q: Urethritis is seen in which of the following conditions?

Reiter's syndrome. The correct answer is **Reiter's syndrome** (now more commonly referred to as **Reactive Arthritis**). **1. Why Reiter’s Syndrome is Correct:** Reiter’s syndrome is a classic form of seronegative spondyloarthropathy that typically develops following a gastrointestinal (e.g., *Salmonella, Shigella*) or urogenital (e.g., *Chlamydia trachomatis*) infection [1, 2]. It is defined by a high-yield clinical triad: * **Urethritis** (or cervicitis) [1, 2] * **Conjunctivitis** (or uveitis) [1] * **Arthritis** (typically asymmetric, oligoarticular, and affecting the lower limbs) [1] The mnemonic **"Can't see, can't pee, can't climb a tree"** is frequently used to remember these features. **2. Why the Other Options are Incorrect:** * **Gout:** A crystal-induced arthropathy caused by monosodium urate deposition [3]. It typically presents as acute monoarthritis (Podagra) and does not involve the mucosal surfaces or the urethra. * **Rheumatoid Arthritis (RA):** A chronic systemic inflammatory disorder characterized by symmetric polyarthritis. While it has extra-articular manifestations (e.g., nodules, episcleritis), urethritis is not a feature. * **Polyarteritis Nodosa (PAN):** A systemic necrotizing vasculitis of medium-sized arteries. It commonly involves the kidneys (renal hypertension), skin, and nerves (mononeuritis multiplex), but does not cause primary urethritis. **Clinical Pearls for NEET-PG:** * **HLA-B27 Association:** Approximately 75-90% of patients with Reactive Arthritis are HLA-B27 positive [2]. * **Cutaneous Findings:** Look for **Keratoderma blennorrhagicum** (pustular lesions on palms/soles) and **Circinate balanitis** (painless ulcers on the glans penis) [1]. * **Joint Involvement:** It is the most common cause of non-traumatic inflammatory monoarthritis/oligoarthritis in young adults [1].

Q: What is the most common presentation of Wegener's granulomatosis?

Sinusitis. **Explanation:** **Granulomatosis with Polyangiitis (GPA)**, formerly known as Wegener’s granulomatosis, is a systemic necrotizing vasculitis that typically involves the triad of the upper respiratory tract, lower respiratory tract, and kidneys [1]. **Why Sinusitis is the correct answer:** The **upper respiratory tract** is the most frequently involved site at the time of initial presentation, occurring in over **90% of patients**. Chronic sinusitis is the most common clinical manifestation, often accompanied by nasal crusting, epistaxis, and otitis media. Over time, this can lead to bony destruction, resulting in the classic **saddle-nose deformity**. **Analysis of Incorrect Options:** * **A. Fever:** While constitutional symptoms like fever, weight loss, and malaise are common in systemic vasculitis, they are non-specific and usually secondary to the underlying inflammatory process rather than the primary presenting feature [1]. * **C. Glomerulonephritis:** Renal involvement (Pauci-immune crescentic glomerulonephritis) occurs in about 75–80% of patients during the disease course but is present in only **20% at initial presentation**. It is a major cause of morbidity but not the most common initial sign. * **D. Diffuse pulmonary infiltrate:** Lung involvement occurs in about 85% of cases, typically presenting as **nodules or fixed cavities** rather than diffuse infiltrates (which are more characteristic of Goodpasture syndrome or SLE). **NEET-PG High-Yield Pearls:** * **Serology:** Highly specific for **c-ANCA** (anti-PR3 antibodies). * **Histology:** Characterized by the triad of vasculitis, mucosal granulomas, and geographic necrosis. * **Treatment:** Induction with Corticosteroids + Cyclophosphamide (or Rituximab). * **Limited GPA:** Refers to disease confined to the respiratory tract without renal involvement.

Question 1

Which of the following is an ANCA negative vasculitis?

Accepted Answer

Polyarteritis nodosa

Answer

Wegener granulomatosis

Answer

Churg-Strauss syndrome

Answer

Microscopic polyangiitis

Question 2

A 40-year-old male complains of exquisite pain and tenderness over the left ankle. There is no history of trauma. The patient is taking a mild diuretic for hypertension. On examination, the ankle is very swollen and tender. There are no other physical examination abnormalities. What is the next step in management?

Accepted Answer

Obtain uric acid level and perform arthrocentesis

Answer

Begin colchicine and broad-spectrum antibiotics

Answer

Begin allopurinol if uric acid level is elevated

Answer

Obtain ankle x-ray to rule out fracture

Question 3

Which of the following is NOT an indication for intravenous immunoglobulin (IVIg)?

Accepted Answer

Systemic lupus erythematosus (SLE)

Answer

Idiopathic thrombocytopenic purpura (ITP)

Answer

Kawasaki disease

Answer

Acute infective polyneuritis

Question 4

A 65-year-old man develops the onset of severe right knee pain over 24 hours. The knee is red, swollen, and tender. The patient does not have fever or systemic symptoms; he has never had severe joint pain before. Plain film of the knee shows linear calcification of the articular cartilage without destructive change. Definitive diagnosis is best made by which of the following?

Accepted Answer

Arthrocentesis and identification of positively birefringent rhomboid crystals

Answer

Serum uric acid

Answer

Serum calcium

Answer

Rheumatoid factor

Question 5

What proportion of patients with Wegener's granulomatosis will have antibodies to Proteinase-3?

Accepted Answer

90%

Answer

10%

Answer

50%

Answer

100%

Question 6

Which of the following statements is false regarding Familial Mediterranean fever?

Accepted Answer

Excessive production of TNF-alpha

Answer

Form of hereditary amyloidosis

Answer

Autosomal recessive inheritance

Answer

Mutation affecting pyrin protein

Question 7

All of the following are true in respect of angioneurotic edema EXCEPT?

Accepted Answer

It manifests as pitting edema

Answer

It is caused by deficiency of complement proteins

Answer

It is more common in females

Answer

It is an autosomal dominant disorder

Question 8

What is the causative agent for rheumatoid arthritis?

Accepted Answer

Mycoplasma

Answer

Mycobacterium avium

Answer

Yersinia

Answer

Herpes virus

Question 9

Urethritis is seen in which of the following conditions?

Accepted Answer

Reiter's syndrome

Answer

Gout

Answer

Rheumatoid arthritis

Answer

Polyarteritis nodosa (PAN)

Question 10

What is the most common presentation of Wegener's granulomatosis?

Accepted Answer

Sinusitis

Answer

Fever

Answer

Glomerulonephritis

Answer

Diffuse pulmonary infiltrate

Rheumatology and Immunology — MCQs

Rheumatology and Immunology — MCQs

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